bugfix: restructure sql moudule folders

[ndr-brt]

What this PR changes/adds

Restructure sql modules to follow a unique convention and to avoid the problem mentioned by #1135
New structure will be:

sql
│── asset-index-sql
│   ├── build.gradle.kts
│   ├── docs
│   ├── README.md
│   └── src
├── build.gradle.kts
├── common-sql
│   ├── build.gradle.kts
│   ├── README.md
│   └── src
├── contract-definition-store-sql
│   ├── build.gradle.kts
│   ├── docs
│   └── src
├── contract-negotiation-store-sql
│   ├── build.gradle.kts
│   ├── docs
│   └── src
├── lease-sql
│   ├── build.gradle.kts
│   └── src
├── policy-store-sql
│   ├── build.gradle.kts
│   ├── docs
│   └── src
├── pool
│   └── apache-commons-pool-sql
└── transfer-process-store-sql
    ├── build.gradle.kts
    ├── doc
    └── src

Why it does that

Seems like gradle cannot handle modules with the same folder name in the project: gradle/gradle#847
Currently there are two store module folder, and this PR avoids this.

Further notes

• make sure that every "leaf" folder into the extensions/sql ends with -sql so that will avoid every kind of conflict.
• include docs folder into the module itself
• rename artifactId to be equal the folder name (this convention should be followed in all the modules)

Linked Issue(s)

Closes #1135

Checklist

• added appropriate tests?
• performed checkstyle check locally?
• added/updated copyright headers?
• documented public classes/methods?
• added/updated relevant documentation?
• added relevant details to the changelog? (skip with label no-changelog)
• formatted title correctly? (take a look at the CONTRIBUTING and styleguide for details)

[codecov-commenter]

Codecov Report

Merging #1154 (5a265bc) into main (24956ec) will increase coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##               main    #1154      +/-   ##
============================================
+ Coverage     62.63%   62.65%   +0.02%     
- Complexity     2973     2981       +8     
============================================
  Files           694      694              
  Lines         15420    15428       +8     
  Branches       1043     1048       +5     
============================================
+ Hits           9658     9667       +9     
+ Misses         5332     5331       -1     
  Partials        430      430              

Impacted Files	Coverage Δ
...ector/sql/asset/index/PostgresSqlAssetQueries.java	100.00% <ø> (ø)
...aspaceconnector/sql/asset/index/SqlAssetIndex.java	81.74% <ø> (ø)
...sql/asset/index/SqlAssetIndexServiceExtension.java	0.00% <ø> (ø)
...spaceconnector/sql/asset/index/SqlAssetTables.java	100.00% <ø> (ø)
...nector/sql/asset/index/SqlConditionExpression.java	100.00% <ø> (ø)
...lipse/dataspaceconnector/sql/ArgumentHandlers.java	100.00% <ø> (ø)
...lipse/dataspaceconnector/sql/SqlQueryExecutor.java	94.44% <ø> (ø)
...or/sql/datasource/ConnectionFactoryDataSource.java	100.00% <ø> (ø)
...ector/sql/datasource/ConnectionPoolDataSource.java	100.00% <ø> (ø)
...tor/sql/datasource/PooledDataSourceConnection.java	8.00% <ø> (ø)
... and 27 more

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[paullatzelsperger]

we should put the "do not create duplicate folder names" convention in some documentation

[florianrusch-zf]

@ndr-brt Any reason why the transfer-process-store-sql/doc folder is written in singular and the others in plural (docs)?

[ndr-brt]

@paullatzelsperger opened an issue about: #1174
@florianrusch-zf just a typo, fixed